The present invention relates to a method of measuring distance by an endoscope that is inserted through the body of a patient for surgical operation to view the interior of the patient's body as well as an endoscope system.
Currently, a trocar is inserted from the body surface of a patient through the interior of the body and various medical instruments are inserted through the trocar to carry out laparoscopic surgery for various treatments and medical examinations in the interior of the body. Although this laparoscopic surgery is less invasive of patients because of making do with a limited incision in the body surface of the patient, it is still required to improve on the visibility of an endoscope and the operability of medical instruments because of the need for performing operations while viewing the interior of the patient's body by way of the endoscope. For laparoscopic surgery, it is required to check up on the interior states of the patient's body with images from the endoscope, and distance measurement is implemented by the endoscope as one method of obtaining detailed information from such images.
Japanese Patent Publication JP(A)3-80824 discloses an endoscope apparatus for measuring the amount of insertion of an endoscope to measure a distance between the endoscope and a subject of interest from a feature point position of the subject on the images before and after insertion.
Japanese Patent No. 3041420 discloses an endoscope system for measuring the amount of movement of an endoscope to compare an image before movement with an image after movement for distance measurement.